RealmResult iterators now detect changes to underlying tableview.

RealmResults now correctly identify any changes to the underlying query tableview and throws a ConcurrentModificationException if detected.

@kneth @bmunkholm @emanuelez 
We can? RealmResults doesn't have a set method currently. Perhaps you are thinking about RealmLink? 

Also it doesn't really makes sense to set an object on a search result. The semantics would be a little confusing, right?